This may be a bit late for some, but I had the same problem. All comms devices cutting out every 90 seconds or so. I have been told by BMW service that my ULF unit is overheating. AU$1570.00 to replace. I intend to install a small vent in the boot floor directly above the unit to see if that helps. If that does not, there is room to install a small 12v fan to the left ofthe unit. So far, I may only be up for AU$20.00. I will let you know how it goes

This may be a bit late for some, but I had the same problem. All comms devices cutting out every 90 seconds or so. I have been told by BMW service that my ULF unit is overheating. AU$1570.00 to replace. I intend to install a small vent in the boot floor directly above the unit to see if that helps. If that does not, there is room to install a small 12v fan to the left ofthe unit. So far, I may only be up for AU$20.00. I will let you know how it goes